JP3395925B2 - Sol-gel film and method for forming the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to unique hemispherical and / or crater-shaped, or hemispherical or / and crater-shaped and wrinkle-shaped fine irregularities (micro) as shown in the attached drawings of the present invention. It has a porous shape with pores, and its shape and size, or the number per unit, etc. can be controlled in various ways, and it has high mechanical strength and chemical resistance, as well as excellent holding power. The present invention also relates to a sol-gel film that also develops and a method for forming the same.

In particular, it is used as a base film or a lower layer film in a multi-layer film laminated on a glass substrate to exert its performance remarkably. For example, a single-layer film and a multi-layer film as a whole are strong without deteriorating optical characteristics. Providing a useful sol-gel film capable of exhibiting various functions and maintaining its function in window materials for construction or automobiles, and glass products with various films, by providing excellent adhesion and excellent wear resistance or durability. Is.

[0003]

2. Description of the Related Art Generally, as a method of forming a porous shape on the surface of a metal oxide film, for example, a method of etching the metal oxide film with hydrofluoric acid or hydrofluoric nitric acid is known.

However, although the above-mentioned porous shape can be formed, in the method of etching the metal oxide film with hydrofluoric acid, hydrofluoric nitric acid or the like, the etching solution, hydrofluoric acid, hydrofluoric nitric acid, etc., is extremely dangerous to the human body. Since it is a difficult substance to handle, it is extremely inferior in workability, and the addition of an etching step causes a decrease in productivity.

Instead of this, for example, Japanese Patent Application Laid-Open No. 51-147976 filed by the present applicant proposes an oxide thin film having a micropit-like surface layer, a multilayer film using the thin film, and a method for forming the same. In a thin film formed on the surface of a glass substrate, at least one compound is selected from the metal alkoxide compound or the metal acetylacetonate compound, and the selected two or more compounds are used. In which the average molecular weight is different, and the two or more compounds are mixed with a solvent to form a coating solution, which is a thin film formed by coating or heating to form a coating solution. 60 nm
It was disclosed that it is a SiO ₂ thin film having a micro-pitted surface layer.

Further, for example, the applicant of the present invention has already filed Japanese Patent Application Laid-Open No. 5-319869 for a sol-gel film and a method for forming the same, and further discloses Japanese Patent Application Laid-Open Nos. 6-16455 and 6-298545.
In the publications, etc., SiO ₂ thin films each having an uneven surface layer,
Various proposals have been made for TiO ₂ · SiO ₂ composite thin films.

Further, for example, in Japanese Patent Laid-Open No. 6-116430,
The water- and oil-repellent film and its manufacturing method are described,
It comprises an inorganic hard film having fine irregularities formed on at least one surface of a plastic film, and a chemical adsorption monomolecular film containing fluorine formed on the fine irregularities of the inorganic hard film through a siloxane bond. It is disclosed that the inorganic hard film is an oxide film or nitride film containing silicon, and the surface thereof is subjected to plasma discharge treatment in a gas containing carbon and fluorine to form minute irregularities.

[0008]

DISCLOSURE OF THE INVENTION The present invention is intended to solve the above-mentioned conventional problems, and an object of the present invention is to eliminate the conventional etching described above and to omit the etching step. A uniquely formed thin film that replaces the previously proposed porous shape such as micropits, which is unique to humans, has excellent adhesion and weather resistance, and is a hard sol-gel film with high safety and work efficiency without troublesome steps. A thin film that is well provided at low cost and has a unique shape with excellent controllability and a porous shape of a specific shape, for example, enhances the holding power of the thin film to be coated. It is to obtain a product that can be equipped with such a function.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has a unique hemispherical shape and / or crater shape, or hemispherical shape and / or crater shape on a glass substrate. It is formed by controlling the surface layer film having a porous shape (a large number of micropores) with a fine uneven pattern that can be said to be wrinkle with good controllability, and has high adhesion and durability and resistance to a glass substrate. Not only does it have abrasion resistance, but it also exerts outstanding holding power etc. while maintaining these characteristics even for the upper layer film that coats the porous thin film, and also exerts the function of the upper layer film outstandingly. It is a thin film, and provides an oxide thin film which is useful not only as a single layer but also as an underlayer film, etc., without any troublesome steps, with high safety, high work efficiency, and low cost.

That is, according to the present invention, a sol solution in which a metal alkoxide compound is hydrolyzed and dehydrated and condensed on the surface of a glass substrate and fine particles or fine particles having a decomposition temperature lower than the solid content in the sol solution are suspended. A solution obtained by mixing a turbid liquid with a solvent is used as a coating liquid, the coating liquid is applied, and the thin film surface layer formed by at least sintering at a heating temperature equal to or higher than the decomposition temperature of the fine particles has a fine porous shape. A sol-gel film.

In addition, the fine porous shape is observed by a scanning electron microscope at a magnification of 15,000 times on the surface of the thin film surface, FIGS. 6 and 7, and by an atomic force microscope. 10. The sol-gel film as described above, characterized in that it has a hemispherical shape and / or a crater shape, or a hemispherical shape and / or a crater shape and a wrinkle-shaped uneven pattern as shown in FIG.

Further, the average particle size of the fine particles is 100
The sol-gel film described above, which is a fluororesin particle having a size of up to 500 nm. Furthermore, the pore shape in the porous thin film surface layer of the above-mentioned thin film, the number of pores per unit area and the control of the pore size and the wrinkle state are controlled by the concentration and average particle size of the fluororesin particles to be mixed, and the solid content in the coating liquid. The sol-gel film as described above, characterized in that the sol-gel film is characterized by the fraction, the selection of the solvent type, and the film thickness of the thin film.

Further, in the coating liquid, the sol-gel film is characterized in that, in the solid content of the coating liquid, the weight ratio of the fluororesin fine particles to the solid content of the sol solution is 0.1 to 2.0.

Furthermore, the sol-gel film described above, wherein the film thickness is at least smaller than the average particle size of the fine particles. Further, a step of preparing a sol solution in which a metal alkoxide compound is hydrolyzed and dehydrated and condensed, a step of preparing a suspension solution in which fine particles or a suspension of fine particles is mixed with a solvent, and the sol solution and the suspension solution And a coating solution, and a step of applying the coating solution on the surface of the glass substrate and forming a thin film surface layer by sintering at a heating temperature equal to or higher than the decomposition temperature of the fine particles. Characteristic method of forming sol-gel film.

In addition, in the step of preparing a sol solution obtained by hydrolyzing and dehydrating and condensing the metal alkoxide compound, at least acetylacetone is added as a stabilizer for the sol solution to water together with the solvent. The method for forming a sol-gel film, which is characterized above.

Further, the method for forming a sol-gel film described above, characterized in that in the step of preparing the suspension solution, at least the preparation is performed by adding water and alcohol. Furthermore, the pore shape in the porous thin film surface layer of the thin film described above, the number of pores per unit area, and the control of the pore size and wrinkle state, the concentration of the fine particles to be mixed and the average particle size, the solid content in the coating liquid. The method for forming a sol-gel film described above, which is performed by selecting the type of the solvent and the film thickness of the thin film.

Furthermore, the average particle size of the fine particles is
The method for forming a sol-gel film as described above, which is 100-500 nm fluororesin particles. Furthermore, in the coating liquid, of the solid content in the coating liquid,
The weight ratio of the fluororesin particles to the solid content of the sol solution is
The method for forming a sol-gel film described above, wherein the sol-gel film has a thickness of 0.1 to 2.0.

Furthermore, the heating temperature in the step of forming the thin film surface layer by sintering at the heating temperature above the decomposition temperature of the fine particles is in the temperature range of 450 ° C. to 680 ° C. Method of forming sol-gel film.

Furthermore, each of the above-mentioned methods for forming a sol-gel film is characterized in that the film thickness in the step of forming the thin film surface layer is at least smaller than the average particle diameter of the fine particles. It is a thing.

Here, as the glass substrate, commercially available soda lime glass used for vehicles such as automobiles, ships, aircraft, and construction can be adopted.
Further, it may be a single glass plate, a bent glass plate, a tempered glass plate, a laminated glass plate, a multilayer glass plate, or a mirror glass plate.

[0021] The surface layer has a hemispherical shape and / or a crater shape, or a hemispherical shape and / or a crater shape and a wrinkle-like uneven pattern (micropore shape).
In the step of preparing a sol solution in which the metal alkoxide compound is hydrolyzed and dehydrated and condensed, at least acetylacetone is added as a stabilizer of the sol solution to water in the step of preparing a sol solution in which the metal alkoxide compound is hydrolyzed and dehydrated and condensed. Then, in the step of preparing the sol solution, for example, at least a specific silica sol solution, and the suspension solution, which is prepared by adding water and alcohol, at least the suspension solution, for example, at least a specific particle size of fluorine. Oxidation by coating a coating solution consisting of a suspension of resin particles or fluororesin particles with a specially prepared suspension solution on glass, heating to a temperature above the decomposition temperature of the fluororesin particles, and sintering. A thin film is formed.

The thin film having a hemispherical and / or crater-like, or hemispherical or / and crater-like, and wrinkle-like, concavo-convex pattern (micropore-like) porous shape has a magnification of 15,000 times as measured by a scanning electron microscope. 6 and 7 of the surface of the thin film surface, 9 of the surface structure of the thin film surface observed by an atomic force microscope, and 10 of the uneven surface cross section of the thin film
As shown by and, not only it has high adhesion to a glass substrate and durability and wear resistance, but also these characteristics are applied to the upper layer film that covers the porous thin film. It is a thin film that can maintain its outstanding holding power, for example, wrapping the coating resin or fine-grained resin in the micropores, etc., and also exert the outstanding function of the upper layer film. It is possible to obtain a useful oxide thin film in a highly safe, efficient and inexpensive manner without complicated steps.

Furthermore, as the silica sol solution, a solution obtained by hydrolyzing and polycondensing a silicon alkoxide or a monomethyl alkoxide as a starting material, for example, CSG-
DI 0600 (solid content (SiO ₂ ) ratio: 6 wt%, Chisso Corporation) or the like is used, and the solution contains another kind of metal, for example,
It may contain alkoxides such as Al, Zr and Ti, monomethyl alkoxides or acetylacetonate salts and polycondensates thereof.

Among them, preferable examples of the alkoxide or monomethyl alkoxide include (monomethyl) methoxide, (monomethyl) ethoxide, (monomethyl) isopropoxide, (monomethyl) n-butoxide and the like, and also as acetylacetonate salt. Preferred examples include acetyl zirconium and titanium acetylacetonate.

Further, the fluororesin is a polymer mainly composed of carbon and fluorine, and includes polytetrafluoroethylene, polychlorofluoroethylene, polyvinylidene fluoride, polyvinyl fluoride, tetrafluoroethylene and hexafluoropropylene. Copolymers of tetrafluoroethylene and ethylene, copolymers of tetrafluoroethylene and perfluoroalkyl vinyl ether, copolymers of chlorotrifluoroethylene and ethylene, and the like, and the fluororesin is silica sol as a powder. It may be mixed in a solution, but it is preferable to mix it as a dispersed suspension.

Among them, the polytetrafluoroethylene powder is, for example, polyflon (M-12, 14, 1)
5), Lubron (L-2, 5) [Daikin Industries, Ltd.],
The copolymer of tetrafluoroethylene and ethylene is, for example, trade name NEOFLON (ETFE) [Daikin Industry Co., Ltd.], and the suspension of polytetrafluoroethylene powder is, for example, trade name of Polyflon (D-1, D-2, D-2C),
Lubron (LDW-10) [Daikin Industries, Ltd.], a suspension of a copolymer of tetrafluoroethylene and hexafluoropropylene is, for example, trade name NEOFLON (ND-1, 2,
4) [Daikin Industry Co., Ltd.], as a suspension of a copolymer powder of tetrafluoroethylene and perfluoroalkyl vinyl ether, for example, trade name NEOFLON (AD-1, AD-
2) [Daikin Industry Co., Ltd.], etc., but from the point of dilution, the above ND-1 (FEP aqueous suspension, average particle size of about 300 nm, resin content 50%, decomposition temperature ℃: start 430 ℃ , Peak 485 ℃, end 590 ℃) or LDW-10 (TFE aqueous suspension, average particle size about 300 nm resin content 50%, decomposition temperature ℃: start 500 ℃, peak 560 ℃, end 640 ℃) is water And dispersibility in methyl alcohol are good, which is preferable.

The average particle size of fine particles such as fluororesin powder is about 100 to 500 nm, preferably 150 to 450 n.
It is about m, more preferably about 200 to 400 nm. Furthermore, if the weight ratio of the solid content, for example, the fluororesin particles to silica, is less than 0.1, the intended porous shape of the surface layer of the membrane cannot be obtained, and if it exceeds 2.0, the film strength is not sufficient and the coating film Since the transparency of the
It is preferably in the range of to 2.0.

When a coating solution is prepared, a lower alcohol such as methyl alcohol, ethyl alcohol or isopropyl alcohol, or a cellosolve such as ethylene glycol monoethyl ether is used as a solvent mixed with the sol solution and the fluororesin. It is possible.

Further, in the step of preparing a sol solution in which the metal alkoxide compound is hydrolyzed and dehydrated and condensed, the order of preparation is preferably a sol solution, acetylacetone and a solvent, and acetylacetone is added to carry out the preparation. And, it acts as a stabilizer of the sol solution against water, and the addition amount thereof is preferably the solid content, for example,
It is about 1.0 to 4.0 mol per 1 mol of SiO ₂ , and 1.0
If it is less than mol, the effect is not obtained, and if it exceeds 4.0 mol, acidity increases and the solution becomes unstable.

Further, in the step of preparing the suspension solution, when water and alcohol are added to carry out at least the preparation, the order of preparation is preferably suspension, water and alcohol. In the system of water and alcohol, which is a solvent for diluting ND-1, when the amount of water is too large, the solution is unstable such as gelation after mixing with silica sol, and when it is too small, for example, the dispersibility of ND-1 is It deteriorates and causes a phase separation phenomenon. Further, this preferable value varies depending on, for example, the SiO ₂ fraction and the amount of ND-1 added, but a preferable range is H ₂ O: CH ₃ O
H = 1: 1 to 10 or so. At this time, when the amount of CH ₃ OH is large (when the amount of H ₂ O is small), ND-1 must be diluted with H ₂ O quickly (stirring for about 3 minutes) to prepare the dipping solution. ₂ O serves to increase the dispersion stability of the suspension solution. Furthermore, if the addition amount of H ₂ O is to be calculated, for example, the weight ratio to the added ND-1 is about 1.0.
It is about 2.0.

Furthermore, the number of pores per unit area in the surface layer of the porous thin film of the above-mentioned thin film can be controlled by the concentration of fine particles such as fluororesin particles in the coating liquid. For example, the weight ratio of ND-1 to SiO ₂ which is the solid content is 0.1 to 2.
It is about 0, and when it is more than about 2.0, the film strength is lowered or the haze value is increased, and the value is preferably about 0.5 to 1.0, and the number of pores per unit area is about 7 to. 30 pieces / μm ² (However, the SiO ₂ fraction is about 2.0w
t% and film thickness of about 50 nm). Further, the pore size can be controlled by the average particle size and the film thickness of fine particles such as fluororesin particles.

The SiO ₂ solid content is 0.5 to
It is about 3.0 wt%, and if it is less than 0.5 wt%, the SiO ₂ content in the coating solution is too diluted to form a film.
If it exceeds, the film thickness becomes too large, and the fine fluorine particles are distributed in the film thickness direction, so that the residual combustion products of the fluororesin may remain during the main firing, and the amount is preferably 0.5 to 2.0 wt%.

Further, the thickness of the oxide coating which is a thin film in the present invention is smaller than the average particle diameter of fine particles, for example, fine particles such as fluororesin powder, and preferably 1/2 of the average particle diameter. Below is about 1/6 or more,
Specifically, for example, if it is about 10 nm or less, the desired porous shape of the surface layer of the film cannot be obtained, and if it exceeds about 150 nm, the mechanical strength of the film cannot be sufficiently obtained and the film is cracked. Since it easily occurs, it is preferably 20 to 100 nm
For example, for automobiles, the thickness is preferably about 50 to 100 nm.

As a method for applying a film to a glass substrate,
Known coating means such as a dipping method, a spray method, a flow coating method, a spin coating method and various printing methods can be appropriately adopted.

Furthermore, when the heating and sintering temperatures of the coating film are below the decomposition temperature of fine particles such as fluororesin particles, the porous shape appearing on the surface layer of the film is sufficiently clear and deep. Therefore, it is preferable that the temperature is not lower than the decomposition temperature of the fine particles such as the resin particles when fluorine is mixed in the coating liquid. In addition, the porous shape formed on the surface layer of the film has a calcination (for example, about 600
A porous metal oxide film having excellent film strength can be obtained without disappearing even if some shrinkage occurs even when the temperature is higher than about ° C. Therefore, for example, about 450 ° C or higher, preferably about 500 ° C or higher and 680 ° C or lower, more preferably about 500 ° C or higher.
It is above 580 ℃ and below 680 ℃.

[0036]

As described above, according to the present invention, a coating solution prepared by mixing a sol solution prepared specifically and a suspension solution prepared specially is applied onto a glass substrate, and the temperature above the decomposition temperature of the contained fine particles is applied. By performing heat sintering with, the cross-sectional state immediately after the coating film formation is as shown in the explanatory view of FIG. 1 for a single fine particle, and the fine particle is separated from the film surface from the coating film on the glass substrate. It protrudes a little and a part of the spherical surface is seen.

Then, the state shown in FIG. 1 is as shown in FIG. 2 during heating and firing of the coating film at a temperature higher than the decomposition temperature of the fine particles, and the fine particles are decomposed and gasified to degas from the coating film to form a hemispherical shape. Alternatively, and / or crater-like, or hemispherical or / and crater-like and wrinkle-like fine irregularities (micropores) are formed.

Then, the heating and sintering is completed from the state shown in FIG.
In this case, as shown in FIG.
One of hemispherical and / or crater-like porous pores
This will complete the two micropores. Again
In addition, as shown in FIGS.
The pore size is about 300 nm or the film thickness is about 50 nm, the pore size is about 10 nm.
0 nm, for example, the pore size (2r) and film thickness (d)
The relationship is (R-d)²+ r²= R ²(However, R: particle size, unit is total
To obtain various micropores such as
It

As described above, the formation of a single micropore shows a large number in the whole thin film on the glass substrate, and the peculiar hemispherical or / and / or unique hemispheres as shown in FIGS. 6 and 7 and 9 and 10. And crater-like, or hemispherical or /
In addition, a surface layer film having a porous shape (a large number of micropores) formed of fine irregularities that can be referred to as craters and wrinkles is formed with good controllability.

In addition to having high adhesion to a glass substrate and durability and abrasion resistance, the upper layer film covering the porous thin film has these properties while maintaining these properties. It is a thin film that exhibits coercive force, such as wrapping a coating resin or a fine granular resin in the micropores, and also exerts the function of the upper layer film outstandingly. The thin film is provided with high safety, high work efficiency and low cost without troublesome steps.

[0041]

EXAMPLES The present invention will be specifically described below with reference to examples. However, the present invention is not limited to the embodiment.

Example 1 A clear float glass substrate having a size of about 100 mm × 100 mm and a thickness of about 2 mm was sequentially washed with a neutral detergent, water rinse, alcohol, dried and then wiped with acetone to form a glass substrate for coating. did.

First, as the first liquid, 78.8 g of CSG-DI 0600 [Chisso Corporation], 15.8 g of acetylacetone (AcAc: 2-4 pentadione), and methyl alcohol (CH ₃ OH) were added.
98.1 g of each is weighed out, and stirred at about 25 ° C. for about 15 to 60 minutes to dilute and prepare a silica sol solution. Acetylacetone serves as a stabilizer for the sol solution against water, and is used as a suspension of, for example, water-soluble fluororesin fine particles (second
It remained unchanged for more than 5 days even after mixing with liquid).

As a second liquid, the fluororesin in the liquid is in a weight ratio of about 0.2 with respect to the solid content of the silica sol solution. (Daikin Industry Co., Ltd.) 1.9 g, water (H ₂ O) 3.8 g, methyl alcohol (CH ₃ OH) 38.0
g Each is weighed out and stirred at about 25 ° C. for about 5 to 10 minutes to prepare a suspension of fluororesin fine particles by diluting.

Next, the first liquid and the second liquid are added and mixed and stirred for about 1 hour to prepare a coating liquid. The solid content (SiO ₂ ) ratio in the coating liquid was about 2.0 wt%. Then, a glass substrate having one surface masked is dipped in the coating solution and coated on one surface of the glass substrate by a dipping method at a pulling rate of about 4 mm / sec to form a film, and then at about 280 to 380 ° C for about 30 minutes. Pre-baking was performed for about 10 minutes, and then heat treatment was performed for main baking at about 620 ° C. for about 10 minutes to form a SiO ₂ thin film with a film thickness of about 75 nm.

The surface shape of the obtained thin film was observed with a scanning electron microscope at a magnification of about 15,000 times. As a result, as shown in FIG. 6, a porous material having peculiar hemispherical and / or crater-shaped micropores was obtained. It is the surface of the shape,
The average pore size was about 150 nm. Furthermore, the average number of pores per unit area was about 5 to 7 holes / μm ² . The initial haze was about 0.2% and the transparency was the same as that of a normal clear glass substrate. Furthermore, in various film evaluations, it was excellent with sufficient adhesion, abrasion resistance, durability and the like.

Example 2 The same glass substrate as in Example 1 was used, and the first liquid was used as the above.
78.8 g of CSG-DI 0600 and 15.8 g of the above acetylacetone
Each was weighed out and a silica sol solution was obtained in the same manner as in Example 1.

Next, as the second liquid, the neoflon ND, which is a suspension of fluororesin particles in the silica sol solution, is prepared so that the fluororesin in the liquid has a ratio of about 1.0 with respect to the solid content of the silica sol solution. −1, 9.5 g of water, 19.0 g of water, and 113.3 g of methyl alcohol were weighed and diluted so that the solid content (SiO ₂ ) ratio in the coating solution was about 2.0 wt%. A coating film and a heat treatment were carried out in the same manner as in Example 1 except that the pulling rate after immersion was set to about 6 mm / sec.
A SiO ₂ thin film with a thickness of about 100 nm was formed.

Obtained SiO₂The surface shape of the thin film is as in Example 1.
When observed in the same manner, the same micropores as in Example 1 were obtained.
It is a porous surface layer that has a shape of
It was about 200 nm on average. Furthermore, per unit area
The average number of holes is about 25-30 / μm ²It was about. Early again
Adhesion, wear resistance, and resistance to haze and various film evaluations
The durability and the like are the same as those in Example 1, and are not sufficiently excellent.
It was.

Example 3 The same glass substrate as in Example 1 was used, and the first liquid was used as the above.
26.3 g of CSG-DI 0600 and 5.9 of the above acetylacetone
255.4 g of methyl alcohol and 255.4 g of methyl alcohol were weighed out and a silica sol solution was obtained in the same manner as in Example 1.

Then, as the second liquid, the neoflon ND, which is a suspension of fluororesin particles in the silica sol solution, is prepared so that the fluororesin in the liquid has a ratio of about 0.5 to the solid content of the silica sol solution. -1 (1.6 g), water (2.4 g) and methyl alcohol (24.0 g) were weighed and diluted so that the solid content (SiO ₂ ) ratio in the coating liquid was about 0.5 wt%. Otherwise, the coating film and the heat treatment were performed in the same manner as in Example 1 to form a SiO ₂ thin film having a film thickness of about 30 nm.

The surface shape of the obtained SiO ₂ thin film was observed in the same manner as in Example 1. As a result, as shown in FIG. 7, a porous surface layer having a micropore shape similar to that in Example 1 was obtained. The average pore size was about 100 nm. Further, the average number of holes per unit area was about 10 to 12 holes / μm ² . Further, the initial haze and the adhesion, abrasion resistance, durability, etc. in the evaluation of various films are the same as in Example 1,
It was excellent enough.

Comparative Example 1 A glass substrate similar to that of Example 1 was coated with CSG- as the first liquid.
50 g of DI 0600 and 100 g of methyl alcohol (CH ₃ OH)
Each was weighed out and a silica sol solution was obtained in the same manner as in Example 1. The solid content of SiO ₂ was about 2.0 wt%.

Using only the sol solution as a coating solution, coating was performed in the same manner as in Example 1, and then the same heat treatment as in Example 1 was performed. When the surface shape of the obtained SiO ₂ thin film was observed in the same manner as in Example 1, it was a flat surface as shown in FIG. 8 and could not be said to be the desired porous shape.

Comparative Example 2 The same glass substrate as in Example 1 was used, and the first liquid was used as the above.
157.5 g of CSG-DI 0600 and 33.5 g of the above acetylacetone
g was weighed out, and a silica sol solution was obtained in the same manner as in Example 1.

Then, as the second liquid, the above-mentioned NEOFLON ND, which is a suspension of fluororesin particles in the silica sol solution, is prepared so that the fluororesin in the liquid has a ratio of about 2.0 with respect to the solid content of the silica sol solution. -1 of 40.0 g, water of 10.0 g, and methyl alcohol of 72.5 g were weighed and diluted so that the solid content (SiO ₂ ) ratio in the coating liquid was about 3.0 wt%. Otherwise, the coating film and the heat treatment were carried out in the same manner as in Example 1 to form a SiO ₂ thin film having a thickness of about 200 nm.

The surface shape of the obtained SiO ₂ thin film was observed in the same manner as in Example 1. As a result, the pore diameter was about 100 nm, but it looked like scale-like spots after the film formation, and the scanning type after sintering. Observation with an electron microscope showed residual combustion products, and it can be said that the film formation was defective, and it could not be said that it was the desired porous shape.

[0058]

As described above, according to the present invention,
A thin film can be easily and inexpensively and efficiently obtained by a simple and easy forming means, a strong porous surface layer having a unique shape can be obtained in the thin film, and the pore diameter and the like can be controlled. Not only as a layer film, but especially in a lower layer film of a multi-layer film, its performance is remarkably exhibited, and it is excellent in adhesion, durability, etc. without impairing optical characteristics, and exhibits outstanding holding power. A utility value that can be widely adopted for various coating films such as window materials for construction or automobiles, various glass articles, etc. such that the function of the upper layer film is also matched and its performance is exhibited more sufficiently in the long term. It is possible to provide a highly useful sol-gel film having a porous surface layer and a method for forming the sol-gel film.

[Brief description of drawings]

FIG. 1 is an explanatory view briefly showing a cross-sectional state of a single fine particle immediately after forming a coating film when forming a sol-gel film of the present invention.

FIG. 2 schematically shows a cross-sectional state before the fine particles are decomposed and gasified and degassed from the coating film during heating and sintering of the coating film shown in FIG. 1 to complete a hemispherical shape and / or a crater shape. FIG.

FIG. 3 is an explanatory view briefly showing one of the porous holes having a hemispherical or crater-shaped cross-sectional state when heating and sintering is completed from the state of the coating film shown in FIG.

FIG. 4 is another embodiment of the sol-gel film of the present invention, in which the thickness of the film and the radius of hemispherical or crater-shaped holes are substantially equal to each other. FIG. 3 is an explanatory view showing the cross-sectional state of FIG. 3 for one of the porous holes.

FIG. 5 is another embodiment of the sol-gel film of the present invention, showing a cross-sectional state of hemispherical or crater-like holes when the radius of the hemispherical or crater-like holes is larger than the thickness of the film. It is explanatory drawing which shows simply about one of the pores of a porous shape.

FIG. 6 is an explanatory view showing a surface state of a sol-gel film having a porous surface layer of the present invention in Example 1, observed by a scanning electron microscope at a magnification of about 15,000 times.

FIG. 7 is an explanatory view showing a surface state of a sol-gel film having a porous surface layer of the present invention in Example 3, observed by a scanning electron microscope at a magnification of about 15,000 times.

FIG. 8 is an explanatory view showing a surface state of a sol-gel film having a flat surface in Comparative Example 1 as a photograph observed with a scanning electron microscope at a magnification of about 15,000 times.

FIG. 9 is an explanatory diagram showing a surface state of a sol-gel film having a porous surface layer according to the present invention as a photograph of a surface structure observed by an atomic force microscope.

10 is an explanatory view showing a surface layer cross-sectional state of a sol-gel film having a porous surface layer of the present invention, showing a concavo-convex state of a cross section obtained by scanning the left and right central portions of the surface structure observation diagram by the atomic force microscope of FIG. 9. is there.

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Claims (7)

(57) [Claims] 1. A sol solution in which a metal alkoxide compound is hydrolyzed and dehydrated and condensed on the surface of a glass substrate, and fine particles or a suspension of fine particles having a decomposition temperature lower than the solid content in the sol solution are used as a solvent. A solution mixed with is used as a coating liquid, the coating liquid is applied, and a thin film surface layer formed by sintering at a heating temperature equal to or higher than the decomposition temperature of the fine particles,
The fine particles are formed by decomposing gasification and degassing from the coating film.
It has a fine porous shape with open pores, and the thickness of the thin film is
A sol-gel film having a thickness smaller than the average particle diameter of the fine particles . 2. The number of holes per unit area of the holes is 7 to 30.
The number of particles / μm ² is the sol-gel film according to claim 1. 3. The fine particles in the coating liquid
Is a fluororesin fine particle, and the weight ratio of the fluororesin fine particle to the solid content of the sol solution is 0.1 to 2.0. 3. The sol-gel film according to claim 1 or 2, wherein 4. A step of preparing a sol solution in which a metal alkoxide compound is hydrolyzed and dehydrated and condensed, a step of preparing a suspension solution in which fine particles or a suspension of fine particles is mixed with a solvent, and the sol solution. From a step of mixing with a suspension solution to form a coating solution, and a step of applying the coating solution on the surface of a glass substrate and forming a thin film surface layer by sintering at a heating temperature equal to or higher than the decomposition temperature of the fine particles. Become the said gold
Hydrolyzed and dehydrated condensed genus alkoxide compounds
In the process of preparing the sol solution, in the water together with the solvent
As a stabilizer for the sol solution,
A method for forming a sol-gel film, characterized in that the preparation is performed by adding seton . 5. The average particle diameter of the fine particles is 100 to 50.
The method for forming a sol-gel film according to claim 4, wherein the fluororesin particles are 0 nm. 6. The coating solution, wherein the weight ratio of the fluororesin fine particles to the solid content of the sol solution in the solid content of the coating solution is 0.1 to 2.0. 4. The method for forming a sol-gel film according to 4 or 5. 7. The sol-gel film according to claim 4, wherein the film thickness in the step of forming the thin film surface layer is smaller than the average particle diameter of the fine particles. Formation method.